siRNA modifications

While chemical modification of siRNA is usually not required, certain modifications can sometimes be useful e.g. to increase stability or cellular uptake. The antisense strand must either have a free 5’-OH (by default) or 5’-phosphate terminus. 5’-end modification of the sense strand RNA does not alter the efficiency of silencing. Various fluorescent dyes can be coupled to the 5’-end of the sense strand oligo to track transfection efficiency of the corresponding duplex. Finally, modifying siRNA with cholesterol is used to facilitate tissue / cellular uptake.

Modifications, such as 2’O-methyl RNA, phosphorothioate bonds, LNA® and a variety of other options are also available.

As a consequence, Eurogentec is continuously extending its list of modifications (see list beside). If the one you need is not included, please inquire.